Shock absorber



W. DOTY SHOCK ABSORBER Feb. 26, 1935.

2 Sheets-Sheet 1 Filed March 25, 1932 QEIIIIUII :.i m

Feb. 26, 1935. w DOTY I 1,992,569

SHOCK ABSORBER Filed March 25,}932 2 Sheets-Sheet 2 Emmi- 6a Patented F b. 26, 1935 TED STATS SHOCK AESE Wade Doty, Jamestown, N. K, 1:

: gnor to 2-Way Shock Absorber Company, End, Jamestown, N. Y... a aeration or New York A daman 7.1. 1

8 2f $5.5 use This invention relates to shock absorbers, more particularly of the hydraulic type, the invention aiming to provide a shock absorber especially adapted for use outside of the automotive field,

a such as for instance in clothes pressing machines,

' centering liquid seal. therefor. I

7 A further object of the invention is to provide improved means for accelerating the speed of travel of the piston toward the end of its travel,

thereby giving a more eiilcient control by building up higher pressures on the long stroke, since as is well known the extent of movement is in proportion to the requirements of shock absorber control.

In the drawings:

Fig. 1 is a side elevation of the ly in section;

Fig. 2 is an enlarged section on line 2-2 of Fig. 1;

Fig. 3 is an enlarged detail sectional view of a part of one end of the cylinder and of the piston,

Fig. 4 is an end elevation of the piston; and

Fig. 5 is a section on line 5-5 of Fig. 4.

In proceeding in accordance with the present invention a cylinder 1 is employed in which is mounted a piston 2 that reciprocates from end to end of the cylinder by virtue of a'rocker arm 3, secured to a rock shaft 4, preferably by means of complementary serrations 5. The piston is invention, partcentrally slotted at 6 and receives the free end of the rocker arm 3 therein, the latter having its free end bifurcated as shown at 'l and having a sliding block 8 mounted between the furcations. The block 8 has a bore through which a transverse pin 9 extends, the pin being'secured to the sides of the piston and extending across the slot 6 thereof. With this construction it will be seen 1 that variation in the length of the leverage of the rocker arm from the center to its extreme of travel is had. The rocker shaft 4 is journalled in a bron ae' bushing 10 which latter at oneend is oil- 50 sealed by means of a packing 11 while its opposite end islikewise .sealed by a packing 12 which is rigidly secured to the cylinder 1 by means of a cup-ring 13. The opposite end of the rocker shaft 4 is sealed by means of a gasket 4', which is held in place by a disk 4." of standard Welch i225, 1932, semi mama plug construction that is expanded into place. An operating arm 14 is secured to a projecting end of the shaft 4 by means of-serrations 15. The cylinder is closed at its ends by means of caps 16 and since the construction. at each end is s alike, a description of one willsuiiice. Each cap is threaded on the exterior of the cylinder and is sealed against liquid leakage by means of packing 1'7. Each cap has a pin 18 threade'dly connected thereto. and secured by a lock nut 19 which 10 bears against a steel ring 20', that in turn bears against packing 20 at the end of the cap, the pin being disposed centrally and axially of the cylinder and having its inner end tapered as shown at 21. The piston is formed at each end with a passage 22 within which the tapered end of the pin is freely received. The end of the piston is counter-bored at 23 and receives a floating bushing 24 therein, the bushing being held within'the counter-bored portion 28 by means of a corrugated ring-like spring 25 which bears against a washer 26 that is fixedly secured to the piston in any suitable manner, such as for example by peaning. The bushing is freely movable both longitudinally and laterally of the axis of the piston, 25

as shown, within ranges determined by the size of the counterbored part 23. The spring 25 functions to hold the bushing in position after the latter has been established by the pin. The bushing moreover is thus held against rattling, and

the collection .of foreign substances on its seatv and consequent. objectionable leakage is prevented. g

The piston is further formed with an axial passageway 2'? in each end thereof, which latter is formed with an intermediate valve seat 28 engaged by a ball valve 29 that is tensioned by a coil spring 30, the outer end of the spring abutting a disk or plate 31 which is fixedly secured in any suitable manner in the end of the piston,

also for example bypeaning. The outer end of each passageway 27 is formed with lateral enlargements 2'7 as-shown' more particularly in Figs. 4 and 5. 4

An angular passageway 32 communicates with in adjusted position by means of a lock nut 35,

the latter engaging against a steel ring 36 which ring in turn engages packing. 3'7 that. seats in a' cavity provided therefor in the cylinder body so as to liquid seal the pin. ;This pin is constructed of a special alloy having a highcoeflicient of expansion. By positioning the screw 34, at a predetermined temperature, to engage against the seat 33 and thereby close the passage against the flow of fluid, the only possible leakage is around the tapered pin as the piston advances toward same. However, upon lowering of the temperature the screw 34 correspondingly contracts and hence leakage past the piston is had in proportion to the viscosity change of the oil following the temperature change. The top of the cylinder or body within which the rocker arm 3 operates is closed by means of a cap 38, which seats against a gasket 39, and is held in position by means of screws 40.

In operation, and referring to 1 as the.

piston moves to the left the ball valve 29 will be seated and with the screw 34 engaged with its seat 33 the liquid must pass around the pin 21 and entering the passage 22 flows into the cylinder. Due to the tapered formation of the pin 21 it will be seen that as the piston initially approaches the inner end of the pin the volume of the passage 22 will be greater than when the piston moves to the position shown in Fig. 1 in which the maximum part of the pin is in the passageway, consequently the volume of the passageagainst further escape of the liquid. Upon lowering of the temperature of the surrounding atmosphere, the thermo-responsive pin 34 will contract and consequently during movement of the piston to theleft of Fig. 1 some of the oil which enters the angular passage 32 can pass through the latter and past the free end of the pin 34 and ententhe cylinder, the amount of the oil which is thus permitted to pass through the passage 32 into the cylinder being obviously governed by the extent of contraction of the pin 34. In addition, the speed of travel of the piston is accelerated as same approaches its extreme of movement due to the sliding connection between the rocker arm 3 and the block 8 thereby further giving more efficient control by building up higher pressure. This lengthening of the leverage of arm 3 results in a greater degree of resistance at the outer or lower end of arm 14. It will therefore be seen that by virtue of the screw 21 and the thermoresponsive pin 34 greater pressure is built upas the piston approaches the extremes of itsmovement toward the ends of the cylinder.

By the provision of a floating bushing 24, it will be apparent that same can freely center itself, consequently there is no likelihood of binding of the pin 21 during reciprocation of the latter relative to and through the bushing.

What is claimed is:

1. In a shock absorber, a liquid containing cylinder having passages communicating with its ends and with its central portion, thermo-responsive means for controlling each of the passages, a piston having passages extending through its ends and into an open central portion thereof, valve controlled passages in the piston for permitting liquid to flow from the cylinder through the piston ends upon movement of the piston in one direction and for preventing such flow upon movement of the piston in the opposite direction, pins secured to the ends of the cylinder and extending into the first named passages of the piston and floating spring pressed bushings carried by the piston and movably receiving the pins therethrough, the free end portions of the pins being tapered whereby upon movement of the piston toward the pins, the latter will gradually decrease the volume of the first named piston passages.

2. In a shock absorber, a liquid containing cylinder having passages communicating with its ends and with its central portion, thermo-responsive means for normally closing each of the passages, a piston having passages extending through its ends and into an open central portion thereof, valve controlled passages in the piston for permitting liquid to flow from the cylinder past the piston ends upon movement of the piston in one direction and for preventing such fiow upon movement of the piston in the opposite direction, pins secured to the ends of the cylinder and extending into the first named passages of the piston, and floating means carried by the piston and movably receiving the pins therethrough the free end portions of the pins being tapered whereby upon movement of the piston toward the pins, the latter will gradually decrease the volume of the first named piston passages.

3. In a shock absorber, a liquid containing cylinder, a piston in the cylinder having valve controlled passages for governing the flow of the liquid and having other passages extending through its ends and opening into the central part of the cylinder, pins connected to the ends of the cylinder and received in said other passages,-and floating spring pressed self-centering bushings carried by the piston and slidably receiving the pins therethrough, and said pins having tapered end portions whereby to gradually decrease the volume of said other passages as the piston approaches its extreme of outward movement and to seal said other passages when the piston reaches its said extreme of movement.

4. In a shock absorber, a liquid containing cylinder, a piston in the cylinder having valve controlled passages for governing the flow of the liquid and having other passages extending through its ends and opening into the central part of the cylinder, pins connected to the ends of the cylinder and received in said other passages, and self-centering means for the pins slidably receiving the pins therethrough and for sealing said other passages when the piston reaches its,

extreme of outward movement, said pins having tapered portions whereby to gradually decrease -the volume of said other passages as the piston approaches its extreme of outward movement.

5. In a shock absorber, a liquid containing cylinder, a piston therein, means for conducting liquid from the cylinder through the piston and into the cylinder, and means to gradually check the flow of the liquid through the piston as the latter approaches its extremes of movement including a self-centering device which upon the piston reaching its extremes of movements substantially stops the flow of the liquid through the piston. 7

6. In a shock absorber, a liquid containing cylinder, a piston therein, means for conducting liquid from the cylinder through the piston and into the cylinder and means to gradually check the flow of the liquid through the piston as the latter approaches its extremes of movement including a self-centering device having movement longitudinally and laterally of the piston for stopping the fiow of theliquid through the piston when the latter reaches its extremes of movements.

7. In a shock absorber, a liquid containing cylinder, a piston therein, means for conducting liquid from the cylinder through the piston and into the cylinder, and means to gradually check the flow of the liquid through the piston as the latter approaches its extremes of movement including a self-centering device having movement longitudinally andlaterallv of the piston tor stopping the flow of the liquid through the piston when the latter reaches its extremes of movements, and means for effecting tension on said 15 self-centering device.

8. In a shock absorber a fluid containing cylinderra piston in theicylinderuhaving valve controlled passages Ior governing the flow of the liquid and having other passages extending through its ends and opening into the central pm or the cylinder, pins connected to the ends 0! the cylinder and received in said other passages, sell-centering means slidably receiving the pins therethrough, said pins having variable cross section whereby to change the volume of said other passages as the piston moves within its cylinder, and means for retaining the self-centering devices in position after the latter is established bysaid pins.

WADE Dow. 15 

